Transitional image for a portion of a display screen



FIG. 1 is a front view of the first image for a transitional image for a portion of a display screen showing my new design; and,

FIG. 2 is a front view of the second image thereof.

The broken line showing of the portion of a display screen, text, images, and lines forms no part of the claimed design. 

The ornamental design for a transitional image for a portion of a display screen, as shown and described. 